A Formula One season which started with plenty of surprise reaches its climax in Sunday’s finale in Brazil where a three-times world champion will be crowned -- either Sebastian Vettel or Fernando Alonso.

After the first eight races saw as many different winners and no real title favourite, the two-times reigning champion Vettel of Red Bull surged in the second half of the campaign to overturn what at times was a 44-point deficit on Ferrari’s Alonso.

Vettel heads into the Interlagos race 13 points clear of Alonso, but the Spaniard remains defiant and believes in his chance to lift the trophy a third time, following titles with Renault in 2005 and 2006.

“There are 71 laps to go that will decide the final outcome: the efforts of several months will all come down to a very short space of time,” Alonso said on the Ferrari website.

“I have confidence in myself and in the team and we will fight right to the end. We are honest with ourselves and our fans: we know we are not super competitive, but if we are still in the running, it’s down to the team which is the best of the lot.” Alonso has found himself on both ends of a title race in a season-ender and in Brazil.

He clinched the 2005 crown prematurely in Brazil and won the 2006 trophy there as well in a finale against Michael Schumacher. But he lost out in dramatic fashion in Interlagos to Kimi Raikkonen in 2007 and to Vettel in the last 2010 race in Abu Dhabi.

The German Vettel, by contrast, has never lost a title race in his young career as after his 2010 heroics he ran away with the 2011 crown he clinched in the fifth-from-last race.

Vettel appears to have all the advantages on his side but given the nature of the sport he and Red Bull remain cautious whether he can match Juan Manuel Fangio and Michael Schumacher by winning three titles in a row.

The Interlagos weather is unpredictable, the latest alternator failure for Red Bull in Mark Webber’s car showed that the high-tech cars are vulnerable, there can be accidents, or drivers can be held up by back-benchers -- the latter helping Lewis Hamilton pass Vettel for victory on Sunday in the United States.

Whether or not those dropped seven points will prove costly remains to be seen, with Vettel saying no more than that “we are in the best possible position.” The superiority of the Red Bull in qualifying could help Vettel to another pole which could keep him out of trouble in the race. Alonso has, however, managed to fight his way up from modest grid positions on many occasions.

Vettel has won in Brazil, in 2010 (with Red Bull also winning from Webber in 2009 and 2011) while Alonso has never topped the Interlagos podium which he will probably have to do to stand a title chance.

Vettel will lift the trophy regardless of Alonso’s result if he finishes fourth or better.

An exciting finale is guaranteed and it is not out of the question that there will be similar drama in Sao Paulo as in 2008, when Ferrari’s local hero Felipe Massa appeared to have won the title by he crossed the line first -- only for Hamilton to lift the trophy after overtaking Timo Glock for fifth place in the second-from-last turn which gave him a one-point advantage.

On Sunday, Hamilton will be driving his last race for McLaren after all his six seasons there, with the Briton moving on to Mercedes in 2013.

There he replaces the record champion Schumacher, who heads into retirement for good on Sunday after three only modest comeback seasons at the German team.

“My departure from Formula One will probably be less emotional for me this time than in 2006, when we were still fighting for the championship and everything was much more intense,” he said.

“This time round, I will be able to pay much more attention to my farewell and hopefully savour it, too. I have had fantastic years in Formula 1 and a lot of support from fans around the world, and I wish to particularly thank them for that. Of course, I would be happiest if I could say goodbye with a strong race.”

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